The weeks ahead may well determine the direction of the Balkan nations within Europe - depending on what the American-led NATO countries do. Will the "ethnic idea" of peoples and states grow stronger, with its attendant wars and hatreds? Or will NATO's intervention plant the seeds for a civil society and the rule of law?

Optimists here feel that NATO countries have decided to end, once and for all, the 19th-century passion for nationalist-based empire. Pessimists, however, see a different scenario: of NATO only coming up with partial measures that will push the problem of the Balkans down the road yet again.

In the optimists' scenario, a Marshall Plan for the Balkans would seal the current borders in concrete and end empire-like aspirations for "Greater" countries - Greater Serbia, Albania, Greece, Croatia, Hungary, or Bulgaria. Strikingly, optimists speak of a military protectorate in Kosovo as if it were a foregone conclusion, almost as if it has already happened. For them, the sunny uplands of democracy, or at least the NATO policemen, are not so far away.

"We are going to see the replacement of the Milosevic regime in Serbia; that is obviously the strategy," says Ljubomir Frckoski, the former foreign minister of Macedonia. "Otherwise, we are just playing at childish games."

Pessimists see a vastly different scenario in which NATO hesitates. The future looks more Darwinian, redder in tooth and claw - a time of further disintegration, fragmentation, uncontrolled mafias, border disputes, and brutal domination of ethnic minorities. For pessimists, the Wild Wild East of Europe will get wilder.

"What I see is a continued slide into chaos, with Europe and the US doing just enough to hold or contain the line," says a senior United Nations official who has served in the former Yugoslavia for several years. "The ongoing scenario for this part of the world looks like breakup and ethnic domination."

Such conflicting visions are not just intellectual or theoretical exercises in this part of the world. They will shape the lives, values, and attitudes of peoples and governments in very pragmatic ways.

What happens next in the former Yugoslavia may be uncertain. But the crude ore of history is still in abundance here. Western attention spans are often quite short, compared with the political pace in the Balkans. But one thing is now clear, experts say: The last 10 years brought the breakup of Yugoslavia, and it is still not over.

In one sense, the war in Slovenia, then Croatia, then Bosnia, and now Kosovo is all one war. What's new this time is that the figure of Slobodan Milosevic has emerged as the central architect of all these conflicts. Before, Mr. Milosevic was in the background: He sat in shadows while the Yugoslav Army pursued the wars in Slovenia and Croatia under his influence. He was partly masked in Bosnia by what many now call his front men, former Bosnian Serb leader Radovan Karadzic, and Gen. Ratko Mladic. Now he is more openly playing his cards, and many here in the Balkans who have watched him outfox the West for a decade are worried that he has a stronger hand than the NATO countries realize.

"Something should have been done to stop the Serbs in Sarajevo," says Saso Ordinavsky, editor of the influential magazine Forum, and one of the optimists. "At this point, the US and NATO need to do the entire job, end once and for all the idea of empire. Half-measures will not be wise."

It's very possible that Kosovo will not be the end. In Macedonia, ethnic tensions brought by refugees from Kosovo are a wake-up call for the possible fracturing of that former Yugoslav country. In Montenegro, still part of the Yugoslav federation, the population is at a flash point over whether to remain in the regime of Milosevic or to go its own way.

What the White House and NATO do with military and diplomatic solutions in the short term, and economic recovery plans in the long term, will have enormous impact on the outcome of these other situations.

Historical influences

Since the turn of the 19th century, the Balkans have imported any number of empire ideas from Russia and Europe. The wish for a large national homeland, such as a Greater Serbia, derives from historical claims on territory that was once - usually in the distant past - either Serbian or Albanian or Croatian, to name a few examples.

Across East Europe, including Yugoslavia, the collapse of the Soviet empire also brought the fall of the Marxist idea of "socialist man" - a creature that would live in equality, if not freedom. In the Balkans, the vacuum created by the fall of the Berlin Wall brought the idea of "ethnic man." The result, most visibly in Serbia, was identity politics with a vengeance. Ethnic groups passionately claimed advantages and superiority over others, relatively unconstrained by Western approaches to minority rights.

After the death of Yugoslav dictator Josip Broz Tito in the 1980s, Milosevic snatched two autonomous provinces in Serbia. In the 1990s, he attempted to unite Serbs in Croatia, and then in Bosnia, in a Greater Serbia. For the past year, Serbs have been forcing out the 90 percent ethnic Albanian population in Kosovo.

Whether NATO was prepared for the high-stakes game played by Milosevic is a hot debate here. In Western capitals the consensus is that NATO was not.

Yet having embarked on a military campaign, and with the NATO 50th-anniversary celebration nine days away, pressure on the alliance is high to create a Kosovo protectorate for ethnic Albanians to return to. On the economic front, ministers and top officials of NATO countries and Russia met in Dresden, Germany, recently to discuss a Marshall Plan-style rebuilding, which could run as high as $10 billion.

German Foreign Minister Joschka Fischer stated the plan intends to make "the Europe of wars and ethnic hatreds a thing of the past."

One place where that job will be complicated is Serbia. NATO bombs have united the proud Serbs passionately behind Milosevic, and the depths of bitterness now felt toward NATO have yet to be sounded.

"I fear that Serbia will be lost for 20 or 30 years," says Srjda Popovic, one of the most famous lawyers in Belgrade and now an migr to the United States. "It will be a wasteland in Europe."